Starting strip connection for discharge lamps



Dec. 22, 1953 w. ELENBAAS ET AL.v 2,653,823

STARTING STRIP CONNECTION FOR DISCHARGE LAMPS Filed April 27, 1949 lrwenators WLLem ELenbaas,

. Dirk Kotkmzan, Adrams A. I-Iurx, bij C I( "1 Their Act'corneg.

Patented 22, lfg

UNITED j STATES TENT orric y STARTING STRIP CONNECTION FOR DISCHARGE LAMPS Application April 27, 1949, Serial No. 89,982

Claims priority, application Netherlands August 5, 1948 3 Claims.

The present invention relates to gaseous electric discharge lamps having elongated tubular envelopes provided with a phosphor coating in the forni of a layer of luminescent powder, and an electrically conductive coating to facilitate starting ofthe main discharge between electrodes disposed at opposite ends of the tubular envelope. Such lamps are disclosed and claimed in oopending application Serial No. 81,724, liled March 16, 194:9, and assigned to the assignee of this application. The conductive coating disclosed in the aforesaid co-pending application consists of a dispersion of a conductive material in an inorganic bonding material united as by being sintered or fused solidly to the inner surface of the tubular glass envelope and in which coating the luminescent material is included locally.

As disclosed. in the co-pending application the conductive coating may be connected directly to one of the electrodes of the tubular lamp and terminate adjacent the opposite electrode to create a difference in potential between the coating and the last-named electrode to facilitate the starting of the main discharge in the lamp. The direct electrical connection to a main discharge supporting electrode is not required after the main discharge has started, however, and it would be desirable to break this connection after starting of the main discharge. Breaking the direct connection may be done at the coating but repeated current interruptions at this point result in damage to the coating and less positive contact therewith being established. It is necessary, therefore, that the connection at the coating be mechanically and electrically positive and permanent and the principal object of the present invention is to provide such a connection and a method of making it. Further objects and advantages of the invention will appear `from the following description of species thereof and from the appended claims.

In accordance with the invention the connecting means, at least at the part thereof engaging the conducting coating, consists of chrome-iron which is rmly united with the conducting coating. A firm permanent contact not only between the connecting means and the coating but also between the connecting means and the glass wall of the envelope is secured by heating the engaging parts of the coating and the connecting means as in the manner described hereinafter.

In the drawing and accompanying part of this specification species of the invention are shown in which Fig. l is an elevational, partly sectional and diagrammatical view of a gaseous electric discharge lamp embodying the invention, and Fig.

2 is a similar View of one end of a similar lamp luminescent powder on the inner surface thereof.

The coating Il extends substantially the full length of the tube and around `its entire inner circumference. An electrically conducting coating i? in the forni of a strip extends along the envelope i between and beyond the electrodes 2 and 3. The conducting coating 5 and the phosphor coating ai at the location of the conducting coating form one coating which is fused to the glassenvelope l so as to be nrmly adherent thereto.

The conducting coating i is electrically connected to the electrode 2 by a metal conductor 6 which is preferably in the form of a strip. A.

chrome-iron strip has been found most satisfactory for this purpose and the connection between the strip t and the conducting strips ii may be made by heating This heating may be done either before or after theelectrode mounts are fused into the ends of the envelope l. If the point i is heated before the electrode mounts the envelope the strip l; must be of sufficient flexibility and length to establish the connection. If the heating at point 'l is done after the electrode mounts are united with the envelope l, the conductor t may be shorter and stiffer. In the latter case, the connection between the coating 5 and the conductor t may be established ing the portion of envelope i opposite point l' with a small gas flame. This local heating at point produces a firm permanent connection between the strip '5 and the glass wall i.

It is not necessary that the conductor e be connected directly to the electrode i. as, shown in Fig. 2, the conductor Ei may be secured vpermanently to a support wire 5 partially embedded the electrode mount and to which a bimetal strip tima-y be fastened in such manner that the strip 9 engages anextension lil of one or" the current leads for the electrode 2 when the strip s is cold. On starting of the main discharge between the electrodes, the strip e is heated by such discharge and opens the circuit including the conductor t and the conducting coating 5. Y

The conducting strip 5 may be deposited on the phosphor coating l by using a roller 3 mm. wide. The deposited material preferably conpoint i of the strip t locally.

are joined to the end ofl by heat- 3 sists of a liquid dispersion of equal weight quantities of nely divided silver oxide AgzO in an enamel having the following batch composition:

Grams Pb304 5,400 B203 .2,075 S102 400 C0CO3 150 M1102 '75 The equal weight quantities ofthe metal oxide and the enamel are suspended in an equal quantity by Weight of butanol and after being deposited as described above the dispersion is dried and then heated to unite the conducting coating ous bonding material united with the surface of said envelope and including a portion of said phosphor coating, said conductor means being permanently connected to said strip and consisting of chrome-iron at the part thereof united with said strip.

2. An electric discharge lamp comprising an envelope containing an ionizable gaseous atmosphere and having spaced electrodes sealed therein, a phosphor coating on its inner surface, an electrically conducting strip on said surface and extending between said electrodes, and conductor means including a therrnostaticy switch connecting said strip to an electrode when cold for facilitating the starting of a discharge between said electrodes and disconnecting said strip from said. electrode during operation of said lamp, said conducting strip comprising nely divided metal particles in a vitreous bonding material united with the surface of said envelope and including a portion of said phosphor coating, said conductor means being permanently connected to said strip and consisting of chrome-iron at the part thereof united with said strip.

3. An electric discharge lamp comprising an envelopek containing an ionizable gaseous atmosphere and having spaced electrodes sealed therea phosphor coating on its inner surface, an electrically conducting strip on said surface and extending between said electrodes, and conductor means electrically connecting said strip to an electrode for facilitating the starting of a discharge between said electrodes, said strip comprising nely divided silver particles in a leadsilicate bonding material united with the surface of said envelope and including a portion of said phosphor coating, said conductor means being permanently connected to said strip and consisting of chrome-iron at the part thereof united with said strip.

WILLEM ELEN'BAAS. DIRK KOLKMAN. ADRIANUS A. HURX.

References Cited in the file of this patent UNTED STATES PATENTS Number Name Date 1,984,428l Piram' Dec. 18, 1934 2,020,737 Piran Nov. 12, 1935 2,094,647 Freitag Oct. 5, 1937 2,114,535- Kirsten Apr. 19, 1938 2,156,068 Ruttenauer Apr. 25, 1939 2,462,336 Rufl Feb. 22I 1949 2,491,854 Force Dec. 20, 1949 

